Julius Caesar, Pope Gregory XIII, Gilbert & Sullivan, and Lenin
More than you ever wanted to know about February 29
With cameo appearances by Cleopatra and the Venerable Bede.
For some ridiculous reason, to which, however,
I have no desire to be disloyal
Some person in authority, I don’t know who,
Very likely the Astronomer Royal
Has decided that although for such a beastly month as February
Twenty-eight days as a rule are plenty
One year in every four, his days shall be numbered as nine-and-twenty.— Gilbert and Sullivan, The Pirates of Penzance (1879)
An Unusual Investment Decision.
If you’ve visited me in my office, I may have shown you hanging in a frame on the wall a bond that I know will never pay interest or return its principal. I knew that when I bought it, and yet I bought it at par (face value). It was a bond issued by the City of Moscow in 1912, in a series denominated in various currencies. The version on my wall was for £20, and that’s what I paid when I bought it from a street vendor selling old documents out of a satchel outside the Green Park tube station in Piccadilly in London sometime in the early 1990s. I’ve spent £20 or its equivalent more foolishly many times in my life.
Aside from my general interest in things Russian (if you’ve missed that here at Medium of Exchange. then you aren’t paying attention), I like this bond because it has a number of interesting features. For this Leap Year note, I’ll concentrate on the coupons. The original holder of the bond never seems to have tried to collect the interest on the bond from 1918 on, so the coupons for those later interest payments remain attached to the bond – no bonus points for guessing why. The wording of the coupons goes something like this: “13-th coupon of the 4½ % Bond. There will be paid to the holder within 10 years, from the 1/14 May 1919, 4 roubles 25 cop. = £ 0.9 …” Before you try the arithmetic, yes, these were semiannual coupons, but don’t forget that the £0.9 meant 9 shillings – trust me, it works out to 4½%.
But what about the curious date? What does 1/14 May 1919 mean? For the full answer, and aren’t you glad you asked, we need to go back to that person in authority who set in motion the chain of calendar reforms that result in the rule that “one year in every four his [February’s] days shall be numbered as nine-and-twenty.” As we’ll see, that isn’t really the rule, but anyway, the person in authority was Julius Caesar – and the story goes back to days that even he would have regarded as antiquity.
Coupons from my City of Moscow bond.
Julius Caesar and the Years of Confusion.
The basic problem with calendars is that the natural rhythms that govern our lives correspond well to terrestrial days, lunar months, and solar years, but days, months, and years don’t correspond with each other.
Calendars through history have adopted a variety of strategies for dealing with the problem of lining up days, months, and years. Mostly they use some form of intercalation, or adding units of time to an otherwise standard year. The exception is the Islamic calendar, which rigidly comprises twelve lunar months, around 354 days (approximately, since a month in a proper lunar calendar has to start on the day of a new moon, so the number of days in twelve lunar months varies a little). The Quran forbids intercalation, so the Islamic year is about 11 days shorter than the solar year (and the secular year), and the Muslim festivals back up by about a week and a half against the secular calendar each year. The holy month of Ramadan, for example, isn’t always in the same season of the year.
The Hebrew calendar, also a lunar one, solves the problem with intercalary (or “Leap”) months, adding an extra month of Adar (“Adar Aleph”) in years 3, 6, 8, 11, 14, 17, and 19 of a nineteen-year cycle. The Hebrew calendar has so many other specific rules and exceptions that it takes a rabbi to understand it.
The ancient Romans made such a mess of their calendar that by the time of Julius Caesar, contemporary sources called the period the “years of confusion.” Roman mythology attributed the original, ancient Roman calendar, to Romulus himself. It started in March and ended in December, following the rhythms of the agricultural year. The Romulan calendar was ten months long, and ran 304 days. It basically didn’t bother with the days between the end of December and the spring planting, which is pretty early in the area near Rome. This ten-month calendar explains why the names of the ninth, tenth, eleventh, and twelfth months of our modern calendar take their names from the Latin words for seven (septem), eight (octo), nine (novem), and ten (decem).
At some point, Rome adopted a calendar of twelve lunar months (adding January and February) and 355 days. The increase to 355 days (as opposed to the Islamic 354) may have to do with a Roman superstition favoring odd numbers. Of course, to get 355 days out of 12 months, at least one of those months has to have an even number of days. They gave the second month 28 days, and devoted it to rites of purification (februa). Livy (Early History of Rome, I.19) attributes the change to Numa Pompilius, the second king of Rome (715-673 BCE), but some historians believe the publication of this lunar calendar probably dates to 450 BCE, when it was part of the Twelve Tables of the Decemvirs.
The Roman lunar year, of course, was about ten days too short. Without some kind of intercalation, “Harvest festivals did not come in summer nor those of the vintage in the autumn.” (Suetonius, Life of Julius, XL.1). They adopted a solution so convoluted that their imperial successors in Byzantium would have shaken their heads over it. The scheme was to add a shortened intercalary month, Mercedonius, of 22 or 23 days after February 23 (the sixth day before the Kalends of March) more or less every other year. Keeping this calendar in line with the solar year would have required adding a Mercedonius month in about eleven of every 24 years. But the Romans made the calendar a political question by leaving it to the college of pontifices (the pontiffs) to determine each year whether or not to have an intercalation. The occurrence (or not) of intercalary months fell hostage to superstition (the Romans considered it inauspicious) and powerful interest groups, who might wish to extend or shorten a political term, or advance or delay the payment of debts.
During the Gallic wars in the middle of the first century BCE the calendar situation became hopeless. The pontifices were reluctant to introduce an inauspicious intercalation during the wars, and anyway, declaring an intercalation required the Pontifex maximus to be in Rome in February. That was Julius Caesar, and he was off in Gaul for so long that intercalations just didn’t happen often enough, and the Roman calendar drifted ninety days away from its solar benchmarks.
Julius Caesar’s wanderings, you’ll recall, took him to Egypt. Tradition has it that while consorting with Cleopatra, Caesar learned of a practical solar calendar, which he introduced in 46 BCE when he returned to Rome and became dictator. His first step, as with other major calendar adjustments, was to bring the calendar back in line with the seasons. On the advice of the Alexandrian astronomer Sosigenes, Caesar simply tacked the missing ninety days onto the end of 46 BCE, with the result that that final “year of confusion” was 445 days long. 45 BCE was the first year reckoned according to the new solar calendar.
Sosigenes apparently knew that the solar year is approximately 365-1/4 days long. Julius Caesar’s calendar had twelve months, alternating between thirty-one and thirty days, except that February had twenty-nine days three years out of four, and thirty days in the fourth year. As a holdover from the days of the Mercedonius months, the extra day in Leap Years was basically a doubling of February 24, the sixth day (sextus) before the Kalends of March. For legal purposes it was a single day, 48 hours long. The Romans called the doubled day bissextus, so pedants call Leap Years bissextile years.
The new calendar had been in place for a little over a year when Julius Caesar was assassinated (on March 15, which really was the Ides of March, 44 BCE, which even Rome’s seers didn’t call 44 BCE). The Romans renamed Quinctilis, the seventh month, the month of his birth, for him – think of July – though the new name didn’t really stick until a comet appeared during games that Octavian (Caesar Augustus) was holding in his honor.
The Romans lost something in translating Sosigenes’s advice. They counted items in their calendars inclusively, so they mistook Sosigenes’s advice to add a day every fourth year, and added a bissextile day every three years instead. The problem became obvious surprisingly fast, and Augustus suspended intercalation from 9 BCE to 8 CE. Bissextile years resumed from 8 CE, but now every four years, as originally intended. At about the same time, Rome renamed Sextilis, the eighth month of the year, for Augustus (our August). The renaming caused an additional difficulty, as Julius Caesar’s original scheme had given the seventh month 31 days and the eighth month 30. Not wanting to show disrespect to Augustus, the Roman Senate gave his month a 31st day, to equal July. They took the day from February, reducing that month to its original length of 28 days in ordinary years (29 in leap years). They also flipped the day counts of the months of September through December, so as not to have three consecutive 31-day months.
Papal Bull.
The Julian Calendar, with Augustus’s reform, persisted for sixteen centuries. At some point the intercalary day shifted to the end of February, but writers as late as the Venerable Bede in 725 refer to the bissextile day six days before the first of March.
The Julian Calendar is almost, but not quite, right. The trouble became apparent because of the problem of pegging the great moveable feast of the Christian calendar, Easter. Both historical and liturgical logic suggest that the feast should fall on the Sunday during Passover. But the First Council of Nicaea in 325 seemed determined not to allow the rabbis to determine the date of Easter (they might not have been able to figure out the Hebrew calendar anyway). So, they adopted a rule that is only slightly simpler. Easter would fall each year on the first Sunday after the first full moon after the Vernal Equinox. Passover does start on a full moon – in most years, the first full moon after the Vernal Equinox. But Easter and Passover are sometimes a lunar month apart, mostly in years in which the Hebrew calendar has an intercalary month.
Anyway, now determining the date of the Vernal Equinox took on substantial importance in the Catholic Church. Some European cathedrals function as solar observatories, with a small hole at a particular spot in the roof, an obelisk at a certain location, and a mark on the floor. The shadow of the obelisk reaches the mark on the floor at the equinox. The trouble is that the solar year is just slightly less than 365-1/4 days long, and by the sixteenth century CE, the Vernal Equinox had backed up to around March 11. Advisors to Pope Gregory XIII persuaded him to promulgate a bull, dated February 24, 1582, correcting the problem. Pope Gregory decreed that century years would not be leap years, unless also divisible by 400 (so 1900 was not a leap year, but 2000 was). Thus, leap years occur not once in every four years, but 97 times in every 400. In addition, Gregory decreed a one-time, ten-day correction. The day after Thursday, October 4, 1582 was Friday, October 15, 1582, and the Gregorian Calendar, which we use as our civil calendar today, was underway.
Well, it was underway in the Catholic world. Protestant countries were reluctant to follow Pope Gregory’s lead, and different ones adopted the Gregorian Calendar at different times and in different ways. Sweden, for example, was the only country since the time of Augustus to have a February 30 (one time only, in 1712). Most relevant to us in the USA, the British Empire conformed to the Gregorian calendar in 1752, making the now required 11-day adjustment (the day after Wednesday, September 2, 1752 was Thursday, September 14, 1752 in Britain, and therefore in Britain’s American colonies). Somewhere deep in my memory is something about how George Washington’s birthday isn’t really February 22, and it has something to do with the fact that this adjustment took place during his lifetime.
Lenin Leans In.
You may also have heard somewhere along the line that the October Revolution really took place in November. Well, sort of. Russia was the last country in Europe to adopt the Gregorian calendar, so at the time of that event, it was October in Russia and November in the rest of Europe. But the discrepancy would soon be no more. Lenin apparently felt, or at least said, that the Bolshevik Revolution was the precursor to world revolution, and the Bolsheviks enacted a decree, said to be symbolic of the aspiration that a single chronometer would mark the beating of the hearts of all the world’s proletarians, adopting the Gregorian calendar to conform to the usage of the rest of Europe. By then the required adjustment was 13 days, which they skipped after January 31, 1918. In Russia in that year, the “beastly month of February” was only 15 days long, which may have eased the transition.
So now we have the solution to the mystery of my bond coupons. Starting sometime in the 18th Century, and surely in the 19th, a great deal of commercial and diplomatic correspondence went back and forth between Russia and other countries. Both sides recognized the potential for confusion in dates, so a convention arose of writing dates as reckoned in both calendars, separated by a slash. “1/14 May” would have been the day the Russians considered May 1, and the British considered May 14. Of course, by the time that date rolled around in 1918, the Russians considered it May 14 too, but there would still have been no ambiguity. A few mid-19th Century letters between California and the Russian settlements in Alaska reflect one more nicety. Since the International Date Line did not yet exist, the Russians, counting forward from St. Petersburg, were always a day ahead of the Californians.
Back to Gilbert and Sullivan.
Gilbert and Sullivan’s Pirates of Penzance turns on a bit of tomfoolery about leap years. At the start of the opera we learn that Frederick, the protagonist, has just attained the age of 21, and is now free of his indenture as an apprentice to a pirate (a bit of tomfoolery in itself). Unfortunately, we learn, the indenture was poorly drafted, saying not that he would be free once he had attained the age of 21, but only after his 21st birthday. But he was born on February 29, and he laments “That birthday shall not be reached by me ’til 1940!”
We can date, if we’re so inclined, the action of the opera. The curtain rises with the pirates congratulating Frederick on reaching the age of 21, so we can surmise that the date is March 1. But what year? Well, if 1940 is to be the 21st recurrence of February 29 since he was born, that suggests we date his birth by counting back 21 x 4 = 84 years, to 1856. But wait – there was no February 29 in 1900, so he was born February 29, 1852, and we can date the initial scene of the opera to March 1, 1873.
We live in sort of an interesting moment with respect to the Gregorian calendar. No one alive remembers 1900, yet we have a responsibility to remember on behalf of our children and grandchildren that 2100 won’t be a leap year either. Maybe preserving that knowledge is the real point of this exercise.